Refillable piping bags of the prior art typically include a pouch having an open upper end defining a fill opening, and an open lower end of smaller transverse cross sectional dimension than that of the upper end, defining an outlet end. Typically, the pouch wall is constructed from a durable, impervious fabric that is permanently bonded to a nozzle base at the outlet end, to which base may be selectively connected a nozzle tip of desired cross-sectional shape to provide a pre-determined decorative effect. Improvements relating to such bags are described in the following patent documents:
PatentsU.S. Pat. No. 5,931,346 WallaysU.S. Pat. No. 5,026,194 LewisU.S. Pat. No. 4,961,517 TkacU.S. Pat. No. 4,844,917 DeLorimiereU.S. Pat. No. 4,776,488 GurzanU.S. Pat. No. 4,205,765 MayApplicationsU.S. Pat. No. 6,179,165B1 Knight et alEP A 0757006 (Ooms)GB A 2237224 (Craig)EP A 02 790 663.5 (Folkmar)It is well established that fabric piping bags are often contaminated with pathogens even after cleansing in a manner to which they would be commonly subject in a domestic or small scale commercial facility.
It is known to provide disposable piping bags in the form of kits. Such kits will normally comprise several plastic pouches, usually distributed in a flat configuration, and one or more nozzles each having a different outlet shape to provide different aesthetic effects, which nozzles are intended to be recovered after use so as to be usable with another pouch. The pouches are shaped such that when filled they will assume a conical configuration, at least at the outlet end thereof. The nozzles of early forms of such kits were of one part and included a tubular body with a conical portion intended to be received within the conical outlet end of a pouch in tightly wedged relation, so as to create a fluid-tight seal therebetween. However, reactive forces between the stretched end of the pouch and the conical body portion of the nozzle tended to urge the nozzle from its wedged relation, and thereby break the seal. Various proposals have been made to increase the gripping inter-action between the nozzle and the pouch, without significant success. The problem is particularly acute when a preferred material, stainless steel, is used in the construction of the nozzle, due to the low coefficient of friction between this material and most plastic materials from which the pouch may typically be formed.
Much of the thrust of the prior art relating to two-part nozzles has been directed towards creating and retaining a seal between the nozzle base and a disposable pouch with which the nozzle is used. The seals described have been either purely frictional, wherein the nozzle is wedged in position in the restricted neck portion of the pouch, or possibly supplemented by welding of some type. The retention means has been separate from the seating means, and generally comprises complementary screw thread or bayonet elements disposed on the nozzle tip and the nozzle base which coact to hold the tip onto the base and simultaneously to trap the material of the pouch therebetween.
The Ooms patent document describes disposable piping bags using a two-part nozzle comprising a nozzle base and a nozzle tip, wherein the nozzle base is physically joined to the pouch by spot welds. Each of the nozzle parts includes complementary, nesting, conical wall portions with complementary coupling means disposed thereon, with a single start screw thread and a dual start, rectilinear bayonet arrangement being particularly exemplified. The coupling means serves to trap material of the pouch therebetween, and in addition to permit the facile change of nozzle tips when the piping bag is filled. The arrangement is obviously unsuited for assembly from a kit form supplied with separate pouches and nozzles, at least in a domestic environment, and is not intended to permit the recovery of the nozzle base for re-use.
Folkmar (of common inventorship herewith) describes disposable piping bags using a two-part nozzle including a base and a tip, wherein the base is structured to enhance the retention of the base in its wedged relation within the pouch. The tip is joined to the base by cooperating thread means disposed on right circular tubular portions of the nozzle, the thread means also serving to trap material of the pouch so as to assist in retaining the nozzle base in position, as well as to assist in providing a seal between the pouch and the nozzle.
It often arises that it is necessary to apply a considerable pressure to express a medium from a piping bag. This may give rise to the escape of small quantities from the nozzle by a back flow action along a passage between the interior wall of the nozzle tip and the exterior wall of the pouch. At best, this may simply be a nuisance in that the escaping medium will coat the hands of an operator, but it may have more far reaching consequences in permitting the ingress of contaminants into this passage from above the nozzle, and so risking contamination of the medium contained within the pouch. It will be evident from the foregoing that the above mentioned back-flow is susceptible to being prevented by the provision of a seal at any place along the passage. In the Folkmar patent document referenced above, there is illustrated a nozzle tip which is threadably attached to a nozzle base wherein the upper edge of the nozzle tip bears on a shoulder disposed on the base, to sandwich the pouch therebetween. This sandwiching action was described primarily as an adjunct means for securing the pouch to the nozzle base, without consideration of any sealing function to prevent the back-flow of medium from the piping bag, nor was there any consideration of the necessity or desirability of providing such sealing function, and in all events, the arrangement was not satisfactory for providing a back-flow seal.
In a two part nozzle , difficulty in separating the nozzle tip from a piping bag may be experienced where, for example the contents contained in the piping bag is of a type which sets up, such as icing sugar. Accordingly, a relatively high torque force may be required to be applied to separate the parts. Moreover, where the two part nozzle is being used to form a piping bag using a disposable film pouch, as will usually be the case, it may be desirable to apply a relatively high torque force to generate an adequate seal between the nozzle and the pouch.
It is a primary object of this invention to provide a two-part nozzle for piping applications having means for creating an effective seal to resist back-flow.
It is a further object of this invention to provide two-part nozzles with means for creating an effective back-flow seal which may be of use where a piping bag is formed using a disposable pouch or otherwise.
It is a still further object of this invention to provide two part nozzles for use with disposable pouches with improved coupling means. It is another object of this invention to provide an improved kit of parts incorporating a disposable pouch and the improved nozzles of this invention, which are suitable for reliable use in both commercial and domestic environments.
It is yet another object of this invention to provide a two part nozzle with improved gripping means for applying enhanced coupling or decoupling forces to the nozzle.
It is another object of this invention to provide a two part nozzle for the formation of piping bags using disposable film pouches wherein there is provided multiple seals between the nozzle and both the internal and the external wall surface of the pouch so as to improve the attachment of the pouch to the nozzle and reduce leakage.
It is still another object of this invention to provide nozzles and kits of parts for forming piping bags for use in commercial and domestic environments wherein the nozzles may be economically manufactured and which are easily recovered intact for re-use.